The present invention relates to a piston pump for a hydraulic system including a cylindrical bore, a pump piston adapted to reciprocate in the cylindrical bore and bounding as a movable wall a working chamber, and an inlet valve which closes in the way of a non-return valve and has a closure member and a valve seat, the closure member being preloaded by a valve spring which is arranged in a spring housing that cooperates with the pump piston, on the one hand, and with a compression spring preloading the pump piston, on the other hand.
German patent application No. 42 42 420 discloses a pump of this type. The disadvantage of the prior art pump is that it comprises many individual parts, which refers especially to the pump piston. This renders the assembly difficult because mainly the valve spring urges the individual parts apart.
Therefore, an object of the present invention is to further improve upon a generic piston pump so that its assembly is facilitated and its manufacture is thus reduced in costs. An additional objective is to improve the operation of the piston pump.